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bill, dodge master tech
Category: Dodge
Satisfied Customers: 1632
Experience:  25 years with dodge drivability and electrical expert
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2008 Dodge Charger: What is the TCM replacement procedure

Customer Question

What is the TCM replacement procedure for a 2008 Dodge Charger, Police Package, with a NAG1 transmission,
Submitted: 6 years ago.
Category: Dodge
Expert:  Neal replied 6 years ago.

I'm Neal and I am here to assist you. Only accept when you are happy with my assistance. If I can't help I will open your Question to other experts.


Here is the procedure for the TCM


If this does not help, let me know.



The adaptation procedure requires the use of the appropriate scan tool. This program allows the electronic transmission system to re-calibrate itself. This will provide the proper baseline transmission operation. The adaptation procedure should be performed if any of the following procedures are performed:

- Transmission Assembly Replacement
- Transmission Control Module Replacement
- Clutch Plate and/or Seal Replacement
- Electrohydraulic Unit Replacement or Recondition

1. With the scan tool, reset the Transmission adaptives. Resetting the adaptives will set the adaptives to factory settings.

NOTE: Perform the Coast Down Adaptations first. The Transmission Temperature must be greater than 60°C (140°F) and less than 70°C (158°F). Failure to stay within these temperature ranges will void the procedure.

2. Drive the vehicle until the transmission temperature is in the specified range.
3. Perform 4 to 5 coast downs from 5th to 4th gear and then 4th to 3rd gear.

NOTE: For Upshift adaptation, the Transmission temperature must be greater than 60°C (140°F) and less than 100°C (212°F). Failure to stay within these temperature ranges will void this procedure.

4. From a stop, moderately accelerate the vehicle and obtain all forward gear ranges while keeping the Engine RPM below 1800 RPM. Repeat this procedure 4 to 5 times.
5. Obtaining 5th gear may be difficult at 1800 RPM. Allow the transmission to shift into 5th gear at a higher RPM then lower the RPM to 1800 and perform manual shifts between 4th and 5th gears using the shift lever.
6. The TCM will store the adaptives every 10 minutes. After completion of the adaptation procedure make sure the vehicle stays running for at least 10 minutes.
7. It is possible to manually store the adaptives under the 10 minute time frame using the scan tool Store Adaptives procedure.

Customer: replied 6 years ago.

I have that procedure, it states in step 3, to perform coast downs from 5th to 4th, but as i said earlier, the vehicle is in LIMP IN MODE and will not allow a shift out of 2nd gear, 30mph

Expert:  Neal replied 6 years ago.
I will opt out and see if another expert has a suggestion for you.
Customer: replied 6 years ago.
Relist: Inaccurate answer.
Expert:  bill replied 6 years ago.

hi i'm bill
welcome to just answer
please remember I am NOT there in front of you! my answers are based on your information.

you CANNOT perform any adaptation procedure WITHOUT a scan tool, it MUST be a dealer level scan tool such as a OTC Pegasus or solous by snap on BUT even these may not be able to preform the task(depends on the updates available from the company that makes the scan tool) and a Stars Scan or Witech from chrysler MAY be needed.

you MUST first preform the initialize function in the misc functions tab (i am using Witech or starscan info your scan tool will be different) this will allow the proper vin and baseline information to be installed in the new tcm so it can shift, IF THIS IS NOT DONT IT WILL NOT SHIFT, then you must drive it to allow the tcm to adapt to the car

if it is still in limp in after the tcm is initialized there are still codes somewhere that must be addressed

Customer: replied 5 years ago.
Brand new TCM, same part number, i am using starscan scan tool. the p1644 is the only dtc in the vehicle besides a WCM dtc regarding a key fob battery. the module reads the correct VIN number p1644 is active, it can be momentarily cleared but reappears when the key is cycled. i can clear the dtc and perform the initialization procedure, which includes cycling the key when commanded to, where the code reappears. the procedure does not indicate whether the procedure was successful or not, just to clear any additional dtcs that may have been set. i have performed this procedure multiple times then drove the vehicle and no difference.
Expert:  bill replied 5 years ago.

you were correct in replacing the tcm for the first code, i suspect defective tcm.

but first be sure there is the correct battery voltage at pin 29 (pink/black) of the c1 tcm connector and a good solid ground at pin 30 (black) check BOTH with a test light (i make up one with an1157 lamp to be sure the circuit will support a load).

if both are good then the replacement tcm is suspected defective just be sure your starscan software is up to date (10.01 is the latest and final, since starscan is now outdated and no longer supported on the dealer end, the aftermarket may see another update, not sure)